Traditionally, inhalation therapy has played a relatively minor role in the administration of therapeutic agents when compared to more traditional drug administration routes of oral delivery and delivery via injection. Due to drawbacks associated with traditional routes of administration, including slow onset, poor patient compliance, inconvenience, and/or discomfort, alternative administration routes have been sought. Pulmonary delivery is one such alternative administration route which can offer several advantages over the more traditional routes. These advantages include rapid onset, the convenience of patient self-administration, the potential for reduced drug side-effects, ease of delivery by inhalation, the elimination of needles, and the like. Many preclinical and clinical studies with inhaled compounds have demonstrated that efficacy can be achieved both within the lungs and systemically.
However, despite such results, the role of inhalation therapy in the health care field has remained limited mainly to treatment of asthma, in part due to a set of problems unique to the development of inhalable drug formulations, especially formulations for systemic delivery by inhalation. Dry powder formulations, while offering advantages over cumbersome liquid dosage forms and propellant-driven formulations, are prone to aggregation and low flowability phenomena which considerably diminish the efficiency of dry powder-based inhalation therapies.
Thus, there remains a need in the art for devices capable of producing a drug aerosol for delivery by, for example, inhalation or topical application.